U.S. patent number 5,368,136 [Application Number 08/147,158] was granted by the patent office on 1994-11-29 for hydraulic brakes for bicycles.
Invention is credited to Willi Walte.
United States Patent |
5,368,136 |
Walte |
November 29, 1994 |
Hydraulic brakes for bicycles
Abstract
A hydraulic brake for bicycles consisting essentially of a brake
lever fastened on the steering column of a bicycle which works on a
master piston movably arranged in a master cylinder, wherein the
chamber in the cylinder is filled with hydraulic fluid, which is
conducted by way of a hydraulic tube into the chamber of a working
cylinder, in which a main piston is movably arranged, which works
on the brake shoes of the bicycle. Along with lower manufacturing
costs, there is easy interchangeability and a good reliability in
servicing the brake. A single working cylinder is fastened above
the fork of the bicycle and the main piston is connected with a
control head, over which a traction cable is directed, which works
on the usual brake shoes.
Inventors: |
Walte; Willi (CH-9430, St.
Margarethen, DE) |
Family
ID: |
6472001 |
Appl.
No.: |
08/147,158 |
Filed: |
November 3, 1993 |
Foreign Application Priority Data
Current U.S.
Class: |
188/24.22;
188/2D; 188/344; 74/489; 74/502.2; 74/502.4; 74/502.6 |
Current CPC
Class: |
B62L
1/14 (20130101); B62L 3/023 (20130101); Y10T
74/20438 (20150115); Y10T 74/2045 (20150115); Y10T
74/20462 (20150115); Y10T 74/20287 (20150115) |
Current International
Class: |
B62L
3/02 (20060101); B62L 3/00 (20060101); B62L
1/14 (20060101); B62L 1/00 (20060101); B62L
001/06 () |
Field of
Search: |
;188/344,2D,24.11,24.22,24.12,24.13,24.14,24.15,24.16,24.17,24.18,24.19,24.21
;92/99 ;60/594 ;303/9.62 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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3325970 |
|
Jan 1985 |
|
DE |
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3416726 |
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Nov 1985 |
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DE |
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Primary Examiner: Butler; Douglas C.
Attorney, Agent or Firm: Gallagher; Paul H.
Claims
I claim:
1. A hydraulic brake for a bicycle having a steering column, and
having brake shoes, a master cylinder with a master piston and
master cylinder chamber therein, a working cylinder with a main
piston movable therein and a working cylinder chamber therein, the
working cylinder being operably connected with the brake shoes, the
brake including a hydraulic tube connecting the chambers of the
cylinders and having hydraulic fluid in the chambers and tube,
characterized in that,
the brake includes a brake lever mounted on the steering
column,
the bicycle includes a fork (1) adjacent the associated wheel to be
braked,
the working cylinder (9) is constituted by a single cylinder and is
mounted to the fork, and
the bicycle includes an operating head (20) and traction brake
cables (7) operably interconnecting the operating head and the
brake shoes, and
the main piston (10) in the working cylinder being operably
connected with the operating head.
2. A brake according to claim 1 further characterized in that,
the operating head (20) is constructed as a regulating wheel which
is adjustably housed in a piston hole (18) of the main piston
(10).
3. A brake according to claim 1 further characterized in that,
the bicycle includes right and left shoes, and
wherein the traction brake cables (7) are connected with the shoes
respectively and connected together and extending over and operable
engaging the operating head.
4. A brake according to claim 1 further characterized in that,
the operating head is constructed as a suspension stirrup (36),
the suspension stirrup has an upper threaded hole (31),
the brake includes a regulating screw (37) gripped in the threaded
hole and having a threaded pin with a pointed end on and operably
engaging the main piston (10).
5. A brake according to claim 4 further characterized in that,
the shoes (2) are pivotally mounted at one end and have their other
ends free and movable, and
wherein said traction cables (35) having one end secured to the
suspension stirrup (36) and their other ends connected with said
free movable ends of the brake shoes.
6. A brake according to claim 1 further characterized in that,
the operating head (20, 36) has side flange elements (49)
overlapping the working cylinder (9, 10) at an upper end of the
latter thereby protecting the latter against dirt.
7. A brake according to claim 1 further characterized in that,
the brake includes a pressure regulating device (38, 47, 39) for
regulating the hydraulic pressure.
8. A brake according to claim 7 further characterized in that,
the pressure regulating device (38, 47, 39) includes a support (41)
in which a pressure regulating chamber (47) is formed and is
connected with the chamber (15) of the working cylinder (9)
operable for conducting hydraulic fluid, and
which includes a compression spring (43) between the regulating
piston (39) and the working cylinder (9).
9. A brake according to claim 8 further characterized in that,
the brake includes means for adjusting the compression of the
spring (43) for correspondingly controlling the regulating piston
(39).
10. A brake according to claim 8 further characterized in that,
the brake includes means for arresting the displacement of the
pressure regulating piston (39).
11. A brake according to claim 1 further characterized in that,
the brake includes a cone opposite the support (8), and
the brake further includes a hose clamp screw (11) operable in
conjunction with the cone, for closing off the hydraulic tube (22).
Description
The object of the present invention is to provide a hydraulic brake
for bicycles. Such a hydraulic brake is known as a front wheel or
rear wheel brake for bicycles, in which at the steering column,
there is attached a brake lever which works on a master piston
which is adjustably arranged in a master cylinder. The cylinder
chamber, defined by the cylinder and master piston, is filled with
a hydraulic fluid, and the hydraulic pressure thereby increased
works by means of a hydraulic tube on at least one working
cylinder, whose one or several main pistons work on the brake shoes
of the bicycle.
It is known to provide two working cylinders with a corresponding
main piston, whereby the main piston works directly on the brake
block. With this known design form, the working cylinder with its
moveably arranged main piston, is constructed as a brake saddle and
the main piston works directly on the brake shoe.
The disadvantage of that design form is that it is costly since on
each brake block there is attached a working cylinder with an
attached main piston, which significantly raises the production
costs. A further disadvantage is the relatively great
susceptibility to wear and tear, because the entire arrangement is
housed in the dirt-collecting region of the vehicle. A further
disadvantage is that because of the constant relatively high brake
pressure, the front wheel fork must be specially strengthened,
because the main pistons that work against each other, stress the
fork and the fastening screws necessary for supporting the
cantilever brake shoe, to the point of bending.
A further disadvantage of the known arrangement is that the
available brake devices are difficult to retrofit with the known
hydraulic brakes because the dimensions of the different forks and
wheel rims might require an exchange of the main pistons with the
thereto attached brake shoes.
It is therefore the object of the present invention to so construct
a hydraulic brake for bicycles or other two-wheeled vehicles,
characterized in lower cost and easily exchangeable and more
securely operating brakes.
An important feature of the invention is a single working cylinder
attached at the front or rear wheel fork of the bicycle, and the
main piston of this working cylinder is connected with a working
head, which is connected to traction cables, which set directly on
cantilever brake shoes.
In the present case, there is the advantage that the cantilever
brake shoes, which normally are present on bicycles, and the
related traction cables, can be retained, and for the retrofitting
step, an available mechanical cantilever brake of the working
cylinder is attached at the front or rear wheel fork, and then
connected with the master cylinder in the brake lever by means of a
hydraulic tube.
This provides the advantage of a simple interchangeability of the
entire arrangement, because the working cylinder can be screwed
into the fastening hole available on the bicycle, whereby--as
referred to above--the cantilever brake shoes with the related
traction cables remain unaltered.
Thereby the ideal efficiency of the cantilever brake shoes is
combined with a maintenance free and practically friction free
hydraulic operation, which allows several advantages:
By means of the triangle control of the traction cable, the brake
pressure, which works on the cantilever brake shoes, is evenly
transferred over the control head of the working cylinder, whereby
this leads to an even pressure of the cantilever brake shoes.
Thereby there is no longer the danger that the frame must be
oversized if a hydraulic brake is to be built thereon, since the
cantilever brake shoes are preserved unchanged on the vehicle, as
is the sizing of the front or rear wheel fork.
In addition there is the further advantage that now, by means of
the use of a single working cylinder with an attached operating
head, there is an essentially smaller cost in manufacture and
assembly, because it can be fastened directly on the existing
fastening hole for the mechanical operating device of the
cantilever brake shoes.
A further advantage is that the working cylinder with the operating
head is brought out of the wheel region where it is susceptible to
soiling and fastened on the cross bar, in an upper position toward
the handle bar.
Thereby there is no longer the susceptibility to soiling, as with
the previously mentioned known working cylinders, which were
directly attached in the brake shoes themselves.
The previously mentioned fastening hole at the frame, which serves
for holding the single working cylinder, serves simultaneously--in
a known manner--for holding the guard plate and the headlight.
With the use of a single working cylinder in the middle region
between the front wheel and rear wheel fork, and which works evenly
on both traction cables, there is above all the advantage that an
ideal distribution of the brake power on both brake shoes results,
and as a result, the brake cables can be very easily engaged by
shifting the operating head of the brake; when for example the
operating head is constructed as a controlling wheel, which meshes
with a threaded peg in an associated threaded hole in the main
piston, the pedal travel of this operating head can be engaged by
turning the regulating wheel. Thereby the power brake can easily be
shifted.
Disclosed herein are two different design forms, namely in the
first design form the traction cable is directed from the left
brake shoe over the operating head to the right brake shoe, whereby
the operating head takes over the reversing of the traction cable,
while in a second design from, the traction cables are connected at
one end with the swingable part of the brake shoe, and at the other
end, securely yet turnably connected with the operating head. The
engagement of the traction cables is thereupon accomplished with a
regulating screw, without the traction cables needing to be removed
form the operating head.
In another design of the invention, an additional pressure
regulating device is provided with which it is impossible to set
the pressure in the cylinder chamber of the working cylinder.
Herein, a pressure regulating piston is used which is
telescopically arranged in a further cylinder chamber, and under
the load of an adjustable pressure spring the hydraulic fluid is
prepressured in the chamber of the working cylinder.
BRIEF DESCRIPTION OF THE INDIVIDUAL FIGURES OF THE DRAWINGS
FIG. 1, schematic cross section including a hydraulic brake in a
first design form.
FIG. 2, an enlarged cross section through a working cylinder in a
second design form.
In FIG. 1, a fork 1 of a bicycle is connected with a cross bar 32.
In the region of the connection between these two parts, there is a
fastening hole 12 through which a screw (not shown in detail) grips
and fastens the working cylinder 9 of the hydraulic brake.
At the fork 1, cantilever brake shoes 2 are, in a known fashion,
swingably held in the pivot positions 3 and are provided with brake
blocks 4. The brake blocks 4 work in a known fashion on the wheel
rim 5 of either a front or rear tire.
At the free swingable ends of the brake shoes 2, are fastened rods
6 in which an end of a penetrating traction cable 7 is inserted.
This traction cable 7 is directed over an operating head of the
hydraulic brake which, in the form of FIG. 1, is constructed as a
regulating wheel 20. The regulating wheel 20 has a lower threaded
stem 19, which is screwed into a corresponding hole 18 of a main
piston 10. The main piston 10 is sealed by an O-ring 13 in the
chamber 15 of the working cylinder 9, and is moveable therein,
under the influence of the hydraulic fluid.
A support 8 is secured to the working cylinder 9, providing mutual
connection in the region of a threaded hole 21. The hydraulic fluid
is thereby directed by means of a hydraulic tube 22, which is
fastened at the support 8 by means of a hose clamp screw 11. The
hose clamp screw 1I closes up the hydraulic tube by means of a cone
opposite the support 8. The hydraulic tube 22 feeds into a channel
14, the latter feeding into the chamber 15.
On the opposite-lying side, the channel 14 leads to a filler nipple
16, which on its upper side is provided with a spring loaded
closing ball 17.
The hydraulic pressure is generated by a master cylinder 23 in
which a master piston 24 is movably housed, and closed off with an
O-ring. The master piston 23 has a hole 29 in which the end of a
master piston rod 28 adjustably fits. This master piston rod 28 is
constructed as a thread screw and is adjustably held in a threaded
nut 30 which is turnably arranged in the moveable part of a brake
lever 27. The brake lever 27 is swingably housed in a drag bearing
45 in a main housing 46, and the master piston rod 28 activates the
master piston 24 in the master cylinder 23. The hydraulic tube 22
is fastened and closed off by a hose clamp screw 26 at the main
housing 46. The main housing 46 is fastened by a hose clamp 34 on
the steering column 33 of the bicycle.
By activating the brake lever 27 the master piston 24 (FIG. 1) is
thereby moved to the left, and the pressure in the chamber of the
master cylinder 23 increases and is instantaneously directed
through the hydraulic tube 22 into the chamber 15 of the working
cylinder 9. Thereby the main piston 10 is pushed upward and thereby
also the activating head, which is constructed as the regulating
wheel 20. Thereby the traction cable 7 is simultaneously activated.
In this context it is important that the cantilever brake shoes 2
with the related parts (brake block 4, pivot element) are retained
and need not be replaced with other parts.
For preadjusting the brake pressure, the regulating wheel 20 can be
activated after lifting the traction cable 7, whereupon the
traction cable is thereafter again laid on the regulating wheel
20.
For filling the brakes, hydraulic fluid is injected into the
pressureless system through the screwed in filler nipple 16 over
the closing ball 17, after opening the vent screw 25. The filling
of the system is continued so long as hydraulic fluid exits out of
the vent screw 25, and thereafter the operator closes the vent
screw.
In FIG. 2 the same parts are provided with the same reference
numbers.
The working cylinder 9 has a similar main piston 10, but this main
piston is provided with a different operating head. The operating
head is here constructed as a suspension stirrup 36, to which
traction cables 35 are coupled.
The traction cables 35 are of secure, constant length and are
thereby symmetrically activated and again released.
For controlling the brake power, a regulating screw 37 is provided
which is screwed into a threaded hole 31 of the suspension stirrup
36 and which supports itself with its stud-sided ends on the upper
side of the main piston 10.
In the following a pressure regulating system is described with
which it is possible to preset the brake pressure.
In this construction, in fluid conducting connection to the
previously described channel 14, a further pressure regulating
channel 38 is present, which feeds into a chamber 47 in the support
41. In the chamber 47 a pressure regulating piston 39 is arranged
in a manner that it can be moved and closed, and is engaged by a
compression spring 43. The compression spring is supported with one
end against the pressure regulating piston 39 and with its other
end against a regulating screw 44. By means of screwing in or out
of the pressure regulating screw 44, the pressure strength of the
pressure spring 43 is set and thereby also the pressure of the
pressure regulating piston 39 on the hydraulic fluid in the chamber
15. This enables a presetting of the hydraulic pressure in the
entire system.
In order to block the engagement, in support 41 a rotary element or
plunger 40 is movably arranged in a hole 48, and its stud-sided
ends can be brought into connection with a snap ring groove 42 in
the circumference of the pressure regulating piston 39. Thereby the
displacement of the pressure regulating piston 39 can be
arrested.
Upon activating the brakes, the pressure is increased in the
chamber 47, and the pressure regulating piston, acting against the
pressure spring 43, moves downward, whereby the activation of the
brake works does not occur so abruptly.
In order to disconnect this pressure regulation, a rotary element
40 is provided, which for example in wet weather is activated,
whereby the pressure regulating piston 39 is arrested and the brake
pressure works directly in the chamber 15 and thereby on the main
piston 10.
A further advantage of the invention, in the use of a single
working cylinder and a corresponding single main piston, lies
primarily in that with use of the customary cantilever brakes, even
changing the wheel is especially easy, which with the previously
known hydraulic brakes, with which the main pistons were built
directly in the brake saddle, was not possible. In those cases the
brake saddle must be removed as well, which in not necessary with
the device of the present invention. In both forms, FIGS. 1 and 2,
the operating head 20, 36 additionally shows lateral flange regions
49, which overlap the working cylinder 9 from above and so protect
it against dirt.
* * * * *